Could the effects of air pollution be mediated by the mix of bugs in our airways? It seems that exposure to pollutants correlates with differences in the species of bacteria living in our respiratory tracts. This may be a hidden link between pollution and disease. Numerous studies have shown that air pollution raises our risk of certain conditions, such as heart disease and stroke . Even in the UK, which has relatively clean air, pollution is blamed for up to 50,000 premature deaths a year . Advertisement. Why this link exists, however, is unclear. To look into one possible cause, Jacopo Mariani and his colleagues at the University of Milan, Italy, took nasal swabs from 40 people living in... Full story